Dermatological/cosmetic compositions comprising a retinoid and benzoyl peroxide

ABSTRACT

Dermatological/cosmetic compositions contain, in a physiologically acceptable medium, at least one retinoid, dispersed benzoyl peroxide and a gelling system comprising at least two categories of compounds.

CROSS-REFERENCE TO PROVISIONAL/PCT APPLICATIONS

This application claims priority under 35 U.S.C. §119 of FR 0652967,filed Jul. 13, 2006 and U.S. Provisional Application No. 60/832,092,filed Jul. 21, 2006, and is a continuation/national phase of PCT/EP2007/057091, filed Jul. 11, 2007 and designating the United States(published in the English language on Jan. 17, 2008 as WO 2008/006848A1); each hereby expressly incorporated by reference in its entirety andeach assigned to the assignee hereof.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to dermatological/cosmetic compositionscomprising, formulated into a physiologically acceptable medium, atleast one retinoid, dispersed benzoyl peroxide and a gelling systemwhich comprises at least two particular categories of compounds.

2. Description of Background and/or Related and/or Prior Art

The administration of several classes of active principles is atherapeutic tool that is frequently employed, especially for treatingdermatological disorders.

Specifically, in the treatment of dermatitis it is known to administercorticosteroids such as, for example hydrocortisone, miconazole orbetamethasone valerate, antihistamines (e.g., mizolastine) and/orkeratolytic agents such as salicylic acid. Various anti-fungal agentssuch as allylamine derivatives, triazoles, anti-bacterial oranti-microbial agents such as, for example, antibiotics, quinolones andimidazoles are also conventionally combined in the treatment ofdermatological diseases. Peroxides, D vitamins and retinoids are alsodescribed for the topical treatment of various pathologies associatedwith the skin or mucous membranes, in particular acne.

The combination of several local treatments (antibiotics, retinoids,peroxides, zinc) is also employed in dermatology to increase theeffectiveness of the active principles and to decrease their toxicity(Cunliffe W. J., J. Dermatol. Treat., 2000, 11 (Suppl. 2), 513-514).

The multiple application of various dermatological products may be quitetaxing and demanding for the patient.

The advantage is therefore understood in seeking to obtain a noveltreatment that is effective on dermatological conditions, that has astable composition offering good cosmetic quality, allowing a singleapplication and administration that is pleasant for the patient.

However, the formulation of such a composition poses several problems.

Firstly, the effectiveness of benzoyl peroxide is linked to itsdecomposition when it is placed in contact with skin. Indeed, it is theoxidizing properties of the free radicals produced during thisdecomposition that result in the desired effect. Thus, in order tomaintain an optimal effectiveness of the benzoyl peroxide, it isimportant to prevent its decomposition before use, that is to say duringstorage.

However, benzoyl peroxide is an unstable chemical compound which makesits formulation in finished products difficult.

The solubility and stability of benzoyl peroxide have been studied byChellquist et al. in ethanol, propylene glycol and various mixtures ofpolyethylene glycol 400 (PEG 400) and water (Chellquist E. M. and GormanW. G., Pharm. Res., 1992, Vol. 9: 1341-1346). Benzoyl peroxide proved tobe particularly soluble in PEG 400 and ethanol.

This document furthermore specifies that the stability of benzoylperoxide is strongly influenced by the chemical composition of theformulation and by the storage temperature.

Benzoyl peroxide is extremely reactive and degrades in solution at lowtemperature due to the instability of its peroxide bond.

The authors thus report that benzoyl peroxide in solution degrades moreor less quickly in all the solvents studied, depending on the type ofsolvent and on its concentration.

The degradation times of benzoyl peroxide in PEG 400 (0.5 mg/g), inethanol and in propylene glycol are respectively 1.4, 29 and 53 days at40° C. Such a degradation does not allow the preparation of a productuseful for sale.

Furthermore, it is known that benzoyl peroxide is more stable in waterand propylene glycol when it is in suspension (i.e., in dispersed form),as it is not degraded after being kept for 90 days in these solvents.

Thus, to limit the problem of rapid instability of benzoyl peroxide insolution, it has proved advantageous to formulate the benzoyl peroxidein dispersed form.

Another difficulty to be overcome for preparing a composition comprisingboth benzoyl peroxide and a retinoid is that most retinoids areparticularly sensitive to natural oxidation, to visible light and toultraviolet light, and since benzoyl peroxide is a strong oxidizer thechemical compatibility of these compounds in one and the sameformulation poses numerous stability problems from a physical andchemical viewpoint.

A study on the stability of two retinoids was carried out by combiningtwo commercial products, one containing a retinoid (tretinoin oradapalene) and the second based on benzoyl peroxide (B. Martin et al,Br. J. Dermatol., (1998) 139, (suppl. 52), 8-11).

The presence of the formulation based on benzoyl peroxide causes a veryrapid degradation of the oxidation-sensitive retinoids: it is calculatedthat 50% of the tretinoin is degraded in 2 hours and 95% in 24 hours. Inthe composition in which the retinoid is adapalene, no degradation ofthe adapalene was measured over 24 hours.

This study confirms that the benzoyl peroxide is degraded and degradesthe oxidation-sensitive retinoids over time by gradually releasingbenzoic acid into the initial products.

On the other hand, no indication was given regarding the physicalstability of the two compositions brought together, nor on thetherapeutic activity likely to be obtained at the end by combining thetwo active principles in the same composition.

Nothing would prompt these two active agents to be combined in order toobtain a stable gel-type composition, given that it was commonly knownthat the presence of benzoyl peroxide chemically and physicallydestabilized this type of composition.

However, it is clear that the too rapid degradation of benzoyl peroxideand the chemical degradation of the retinoids is undesirable insofar asit impairs the effectiveness of the composition containing them.

Furthermore, a finished product, in particular when it is apharmaceutical or cosmetic composition, must maintain, throughout itsshelf life, precise physicochemical criteria that make it possible toguarantee its pharmaceutical or cosmetic quality respectively. Amongthese criteria, it is necessary that the rheological properties beretained. They define the behavior and texture of the composition duringapplication, but also the release properties of the active principle[1998 SFSTP Commission Report] and the homogeneity of the product whenthe active principles are present therein in the dispersed state.

In particular, the formulation of benzoyl peroxide and a retinoid in gelform is advantageous for topical treatments, such as those of acne, asit especially avoids maintaining a greasy feel on the skin.

Another difficulty to be overcome for preparing a composition especiallycomprising benzoyl peroxide, when it is in gel form, is that the gellingagents are destabilized by the benzoic acid released during thedegradation of benzoyl peroxide.

Indeed, the most commonly used thickening agents for formulating thesecompositions with benzoyl peroxide are acrylic acid polymers (Carbomer).

However, the use of carbomers in aqueous gel-type compositions does notgive good results in terms of chemical stability of benzoyl peroxide andin terms of rheological stability. As described by Bollinger (Bollinger,Journal of Pharmaceutical Science, 1977, Vol. 5), a loss of 5 to 20%benzoyl peroxide has been observed at the end of 2 months at 40° C.depending on the carbomer neutralizer used. Furthermore, the release ofbenzoic acid causes the depolymerization of the carbomers, causing adrop in viscosity which may result in phase separation.

This instability of benzoyl peroxide gels impairs their effectivenessand their cosmetic quality.

Therefore, the need remains to provide a physically stable gelledcomposition comprising benzoyl peroxide and a retinoid. However, nothingamong the range of therapies proposed to one skilled in this art wouldsuggest the combination, in the same composition, of benzoyl peroxideand a retinoid and several different gelling agents.

SUMMARY OF THE INVENTION

Nonetheless, novel compositions have now surprisingly been developedsatisfying this need, which comprise dispersed, free or encapsulatedbenzoyl peroxide, at least one retinoid and a gelling system comprisingat least two categories of compounds, such compositions having goodphysical stability, that is to say not having a drop in viscosity overtime and at ambient temperature (from 20 to 30° C.), and maintaininggood chemical stability of the two active agents (benzoyl peroxide andretinoid). In particular, no degradation of the active agents isobserved over time and/or at ambient temperature.

The present invention therefore features compositions, especiallypharmaceutical compositions, comprising, formulated into aphysiologically acceptable medium:

at least one retinoid;

benzoyl peroxide; and

a gelling system which comprises at least two categories of compounds,

said categories of compounds being selected from among silicates,cellulose gelling agents and polysaccharide gums, with the proviso thatwhen at least two gelling agents are selected from amongaluminum/magnesium silicate, xanthan gum and hydroxypropyl cellulose,the gelling system is composed of these two gelling agents, or comprisesat least one gelling agent different from these three compounds.

The term “gelling system” means a combination of gelling compounds thatgives the composition a sufficient viscosity to maintain the retinoidand the benzoyl peroxide in suspension, even under the influence, inparticular, of a pH variation due to the release of benzoic acid by thebenzoyl peroxide.

The term “physiologically acceptable medium” means a medium that iscompatible with the skin, the mucous membranes and/or the integuments.

DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OFTHE INVENTION

The compositions according to the invention are preferably in the formof an aqueous gel, which is particularly well suited to the targetpathologies.

A gel is a system comprising at least one phase (in general one or twophases), which is thermodynamically stable, resulting from thecoagulation of a colloidal solution into a three-dimensional network.More specifically, an aqueous gel corresponds to a compositioncontaining, in an aqueous phase, a visco-elastic mass formed fromcolloidal suspensions.

More specifically, the gelling system comprises at least two categoriesof compounds, naturally different and distinct, said categories ofcompounds being selected from among silicates, cellulose gelling agentsand polysaccharide gums.

The term “silicate” is understood in particular to mean clayderivatives, more specifically aluminum and magnesium silicates. Thesilicates are generally obtained from mineral clays having a crystallinelattice that are dissolved and purified in water to optimize the purityand effectiveness of the product. These compounds are especiallymarketed by R. T. Vanderbilt under the trademark VEEGUM® (for example:VEEGUM® HV or VEEGUM® K).

The amount of silicate may vary over a wide range and depends inparticular on the desired viscosity and on the other gelling agentand/or agents present in the composition. To provide an order ofmagnitude, the silicate may be present in the composition according tothe invention in concentrations from 0.1 to 10%, preferably ranging from0.1 to 5% by weight relative to the total weight of the composition.Advantageously, the amount is from 0.5 to 2%, even more preferably from0.8 to 1.8%, such as for example 1%, relative to the total weight of thecomposition.

The term “cellulose gelling agent” means water-soluble polymers derivedfrom cellulose. These polymers form water-soluble ethers (semi-syntheticcellulose) originating from viscous solutions after dissolving in anaqueous solution. Among the cellulose polymers, especially exemplary aremethyl cellulose, ethyl cellulose, hydroxypropylmethyl cellulose,hydroxyethyl cellulose, hydroxylpropyl cellulose, carboxymethylcellulose and hydroxymethyl cellulose. Preferably hydroxypropylmethylcellulose or hydroxyethyl cellulose are used. These compounds areespecially marketed by Dow Chemical under the trademark METHOCEL® (forexample: METHOCEL® E4M) or by Hercules under the trademark NATROSOL®(for example: NATROSOL® 250 HHX).

The amount of cellulose gelling agent may vary over a wide range and inparticular depends on the desired viscosity and on the other gellingagent and/or agents present in the composition. To provide an order ofmagnitude, the cellulose-based gelling agent may be present in thecomposition according to the invention in amounts from 0.1 to 10%,preferably ranging from 0.1 to 5% by weight relative to the total weightof composition. Advantageously, the amount is from 0.5 to 2%, such asfor example 0.5%, 1%, 1.5% or 2% relative to the total weight of thecomposition.

Polysaccharide gums are complex mixtures of several high-molecularweight polysaccharides obtained by exudation from certain plants. Amongthe different types of polysaccharide gums, non-limiting examplesthereof are gum Arabic, gum tragacanth and xanthan gum, amongst anothermarketed by CP Kelco under the trademark XANTURAL® (for example:XANTURAL® 180).

The amount of polysaccharide gum may vary over a wide range and dependsin particular on the desired viscosity and on the other gelling agentand/or agents present in the composition. To provide an order ofmagnitude, the polysaccharide gum may be present in the compositionaccording to the invention in amounts from 0.01 to 5%, preferablyranging from 0.05 to 2% by weight relative to the total weight of thecomposition. Advantageously, the amount is from 0.1 to 0.8% such as, forexample, 0.1%, 0.2% or 0.5% relative to the total weight of thecomposition.

The gelling system may comprise two categories of compounds or threecategories of compounds, said categories of compounds being selectedfrom among silicates, cellulose gelling agents and polysaccharide gums.

According to one particular embodiment, the gelling system comprisingtwo categories of compounds comprises at least one cellulose gellingagent (in particular hydroxypropylmethyl cellulose or hydroxyethylcellulose) in combination with a silicate or a xanthan gum, taking intoaccount the condition indicated above.

According to another particular embodiment, the gelling systemcomprising two categories of compounds comprises at least one silicate,in combination with a polysaccharide gum, taking into account thecondition indicated above.

According to another particular embodiment, the gelling systemcomprising two categories of compounds comprises at least onepolysaccharide gum, in combination with a cellulose gelling agent (inparticular hydroxypropylmethyl cellulose or hydroxyethyl cellulose),taking into account the condition indicated above.

The gelling system may also comprise at least one silicate, at least onecellulose gelling agent and at least one polysaccharide gum, taking intoaccount the condition indicated above.

Among the gelling systems having three categories of compounds,especially exemplary is the combination of polysaccharide gum, silicateand a cellulose gelling agent, taking into account the conditionindicated above.

According to variants of the invention, the subject compositions may, inaddition, comprise an additional gelling agent which may especially beselected from among mixtures of polyacrylamides such as the sodiumacryloyidimethyltaurate copolymer/isohexadecane/polysorbate 80 mixturemarketed under the trademark SIMULGEL 600 by Seppic, thepolyacrylamide/C13-14 isoparaffin/laureth-7 mixture such as, forexample, that marketed under the trademark SEPIGEL 305 by Seppic, thefamily of acrylic polymers coupled to hydrophobic chains such as thePEG-150/decyl/SMDI copolymer marketed under the trademark ACULYN 44(polycondensate comprising at least, as components, a polyethyleneglycol having 150 or 180 moles of ethylene oxide, decyl alcohol andmethylenebis(4-cyclohexylisocyanate) (SMDI), at 35% by weight in amixture of propylene glycol (39%) and water (26%)), the family ofmodified starches such as the modified potato starch marketed under thetrademark STRUCTURE SOLANACE or else mixtures thereof.

The compositions according to the invention contain at least oneretinoid. The term “retinoid” means any compound that binds to RARand/or RXR receptors.

Preferably, the retinoid is a compound selected from among the family ofbenzonaphthalenic retinoids as described in EP 0 199 636, andespecially:

-   6-(3-methylphenyl)-2-naphthoic acid and its methyl ester;-   6-(4-tert-butylphenyl)-2-naphthoic acid and its methyl ester;-   6-(3-tert-butylphenyl)-2-naphthoic acid and its methyl ester;-   6-(3,4-dimethoxyphenyl)-2-naphthoic acid and its methyl ester;-   6-(p-(1-adamantylthio)phenyl)-2-naphthoic acid and its methyl ester;-   6-(3-(1-adamantyl)-4-methoxyphenyl)-2-naphthoic acid (adapalene) and    its methyl ester;-   the methyl ester of    6-[3-(1-adamantyl)-4-tert-butyldimethylsilyloxyphenyl)-2-naphthoic    acid;-   the methyl ester of 6-[3-(1-adamantyl)-4-hydroxyphenyl)-2-naphthoic    acid;-   6-[3-(1-adamantyl)-4-hydroxyphenyl)-2-naphthoic acid;-   the methyl ester of 6-[3-(1-adamantyl)-4-decyloxyphenyl)-2-naphthoic    acid;-   6-[3-(1-adamantyl)-4-decyloxyphenyl)-2-naphthoic acid;-   the methyl ester of 6-[3-(1-adamantyl)-4-hexyloxyphenyl)-2-naphthoic    acid;-   6-[3-(1-adamantyl)-4-hexyloxyphenyl)-2-naphthoic acid;-   the methyl ester of    6-[3-(1-adamantyl)-4-methoxyphenyl)-4-acetoxy-1-methyl-2-naphthoic    acid;-   6-[3-(1-adamantyl)-4-methoxyphenyl)-4-hydroxy-1-methyl-2-naphthoic    acid;-   the methyl ester of    6-[3-(1-adamantyl)-4-methoxyphenyl)-4-hydroxy-1-methyl-2-naphthoic    acid;-   the methyl ester of    6-[3-(1-adamantyl)-4-methoxyphenyl)-1-methyl-2-naphthoic acid;-   6-[3-(1-adamantyl)-4-methoxyphenyl)-1-methyl-2-naphthoic acid;-   6-[3-(1-adamantyl)-4-methoxyphenyl)-2-naphthalene methanol;-   the ethylamide of 6-[3-(1-adamantyl)-4-methoxyphenyl)-2-naphthoic    acid;-   the morpholide of 6-[3-(1-adamantyl)-4-methoxyphenyl)-2-naphthoic    acid;-   the methyl ester of 6-[3-tert-butyl-4-methoxyphenyl)-2-naphthoic    acid;-   6-[3-tert-butyl-4-methoxyphenyl)-2-naphthoic acid;-   the methyl ester of    6-[3-(1,1-dimethyldecyl)-4-methoxyphenyl)-2-naphthoic acid;-   6-[3-(1,1-dimethyldecyl)-4-methoxyphenyl)-2-naphthoic acid.

In particular, adapalene and also its salts will be preferred.

The term “adapalene salts” means the salt formed with a pharmaceuticallyacceptable base, especially mineral bases such as sodium hydroxide,potassium hydroxide and ammonia or organic bases such as lysine,arginine or N-methylglucamine.

The term “adapalene salts” is also understood to mean the salts formedwith fatty amines such as dioctylamine and stearylamine.

Other retinoids may be selected from among those described in thefollowing patents or patent applications: U.S. Pat. Nos. 4,666,941,4,581,380, EP 0 210 929, EP 0 232 199, EP 0 260 162, EP 0 292 348, EP 0325 540, EP 0 359 621, EP 0 409 728, EP 0 409 740, EP 0 552 282, EP 0584 191, EP0 514 264, EP0 514 269, EP0 661 260, EP0 661 258, EP 0 658553, EP 0 679 628, EP 0 679 631, EP 0 679 630, EP 0 708 100, EP 0 709382, EP 0 722 928, EP 0 728 739, EP 0 732 328, EP 0 740 937, EP 0 776885, EP 0 776 881, EP 0 823 903, EP 0 832 057, EP 0 832 081, EP 0 816352, EP 0 826 657, EP 0 874 626, EP 0 934 295, EP 0 915 823, EP 0 882033, EP 0 850 909, EP 0 879 814, EP 0 952 974, EP 0 905 118, EP 0 947496, WO 98/56783, WO 99/10322, WO 99/50239, WO 99/65872.

Of course, the amount of the two active agents, benzoyl peroxide andretinoid, in the composition according to the invention, will depend onthe combination selected and therefore particularly on the retinoid inquestion and on the quality of the desired treatment.

The preferred retinoid concentrations are from 0.0001 to 20% by weightrelative to the total weight of the composition.

Benzoyl peroxide could also be used in the free form or else in anencapsulated form in a form adsorbed on, or absorbed in, any poroussupport.

It could for example be benzoyl peroxide encapsulated in a polymersystem made of porous microspheres, such as for example microspongesmarketed under the trademark MICROSPONGES P009A Benzoyl Peroxide byCardinal Healthcare.

To provide an order of magnitude, the compositions according to theinvention advantageously comprise from 0.0001 to 20% by weight ofbenzoyl peroxide and from 0.0001 to 20% by weight of retinoid relativeto the total weight of the composition, and preferably, respectively,from 0.025 to 10% by weight of benzoyl peroxide and from 0.001 to 10% byweight of retinoid relative to the total weight of the composition.

For example, in compositions for treating acne, benzoyl peroxide ispreferably present at concentrations ranging from 2 to 10% by weight andmore particularly from 2.5 to 5% by weight relative to the total weightof the composition. Retinoid is itself present in this type ofcomposition at concentrations generally ranging from 0.05 to 1% byweight relative to the total weight of the composition.

Advantageously, the particle size of the retinoid and of the benzoylperoxide is such that at least 80% by number of particles, andpreferably at least 90% by number of particles, have a diameter of lessthan 25 μm and at least 99% by number of particles have a diameter ofless than 100 μm.

According to the invention, advantageously, the gel containing thebenzoyl peroxide and a retinoid comprises at least water and may alsocomprise a propenetrating agent and/or a wetting liquid surfactant.

The compositions of the invention may contain one or more propenetratingagents in preferable concentrations ranging from 0.01 to 20% to morepreferably ranging from 2 to 6% by weight relative to the total weightof the composition. Preferably 2, 4 and 5%.

The propenetrating agents should generally not dissolve the activeagents at the percentage employed, should not cause exothermic reactionsthat damage the benzoyl peroxide, should help in the satisfactorydispersion of the active agents and should have anti-foaming properties.Among the propenetrating agents preferably used, without this list beinglimiting, are compounds such as propylene glycol, dipropylene glycol,propylene glycol dipelargonate, lauroglycol and ethoxydiglycol.

The particularly preferred propenetrating agent is propylene glycol.

Advantageously, the compositions according to the invention may alsocontain one or more wetting liquid surfactants in preferableconcentrations ranging from 0.01 to 10% to more preferably ranging from0.1 to 2%. The wetting ability is the tendency of a liquid to spread outover a surface.

Preferably, they are surfactants having a HLB (Hydrophillic LipophilicBalance) of 7 to 12, or else non-ionic surfactants of polyoxyethylenatedand/or polyoxypropylenated copolymer type. They should be liquid so asto easily be incorporated into the composition without it beingnecessary to heat them, the objective being, amongst other things, toobtain a low-temperature manufacturing method, which in no way limitsthe present invention.

Among the wetting agents preferably employed, without this list beinglimiting, are compounds of the family of poloxamers and moreparticularly Poloxamer 124 and/or Poloxamer 182.

The particularly preferred wetting liquid surfactant is Poloxamer 124.

The composition may comprise, in addition, any additive commonly used inthe cosmetic or pharmaceutical field, such as sequestrants,antioxidants, sunscreens, preservatives, fillers, electrolytes,humectants, dyes, common mineral or organic bases or acids, fragrances,essential oils, cosmetic active agents, moisturizers, vitamins,essential fatty acids, sphingolipids, self-tanning compounds such as DHAand skin soothing and protective agents such as allantoin.

Of course, one skilled in this art will take care to select this orthese optional additional compounds, and/or their amount, so that theadvantageous properties of the composition according to the inventionare not, or are not substantially, adversely affected.

These additives may be present in the composition in an amount of 0.001to 20% by weight relative to the total weight of the composition.

Exemplary are, as examples of sequestering agents, ethylenediaminetetracetic acid (EDTA), and also derivatives or salts thereof,dihydroyethylglycine, citric acid, tartric acid, or mixtures thereof.

Exemplary are, as examples of preservatives, benzalkonium chloride,phenoxyethanol, benzyl alcohol, diazolidinylurea, parabens, or mixturesthereof.

Exemplary are, as examples of humectants, glycerol and sorbitol.

In particular, the present invention also features pharmaceutical orcosmetic compositions for topical application to the skin, integumentsor mucous membranes, in the form of an aqueous gel, which comprise,formulated into a physiologically acceptable medium that is compatiblewith topical application to the skin, integuments or mucous membranes,an active phase comprising (expressed as percentage by weight):

20 to 90% of water;

0 to 10%, preferably 0 to 2%, especially 0 to 0.5% of wetting liquidsurfactant;

0 to 20%, preferably 0 to 10%, especially 2 to 5% of propenetratingagent;

0.0001 to 20%, preferably 0.025 to 10% of benzoyl peroxide;

0.0001 to 20%, preferably 0.001 to 10% of retinoid; and

0.11 to 25% of a gelling system as described above.

The aqueous phase of the composition according to the invention maycomprise water, a floral water such as cornflower water, or a spring ornatural mineral water, for example selected from among water fromVittel, waters from the Vichy basin, water from Uriage, water from laRoche Posay, water from la Bourboule, water from Enghien-les-Bains,water from Saint Gervais-les-Bains, water from Néris-les-Bains, waterfrom Allevard-les-Bains, water from Digne, water from Maizières, waterfrom Neyrac-les-Bains, water from Lons-le-Saunier, water from Bonnes,water from Rochefort, water from Saint Christau, water from Furnades andwater from Tercis-les-Bains, water from Avène or water from Aix lesBains.

Said aqueous phase may be present in an amount from 10 to 90% by weightrelative to the total weight of the composition, preferably from 20 to85% by weight.

A preferred composition according to the invention comprises, in water:

2.5% of benzoyl peroxide;

0.1% of adapalene;

0.1% of disodium EDTA;

2%-4% of glycerol;

2%-6%; (preferably 2%, 4% or 5%) of propylene glycol

0%-0.05% of sodium docusate;

2%-4% of a gelling system as described above; and

0.2%-0.5% of Poloxamer 124.

A particularly preferred composition according to the inventioncomprises, in water:

Adapalene 0.1% Benzoyl peroxide qs 2.5% BPO Propylene glycol   4%Poloxamer 124 0.1% Aluminum/magnesium silicate   2% Hydroxyethylcellulose 1.5% Xanthan gum 0.5% Glycerol   2% Sodium docusate 0.05% 

The methods for preparing the compositions according to the inventionare conventional methods that can be carried out by one skilled in thisart.

The present invention also features the composition as describedpreviously as medication.

This invention also features the use of the composition as describedpreviously in cosmetics or in dermatology.

On account of the keratolytic, bactericidal and anti-inflammatoryactivity of benzoyl peroxide and the pronounced activity of retinoids inthe fields of cell differentiation and proliferation, the compositionsof the invention are particularly suitable in the following therapeuticfields:

1) for treating dermatological conditions or afflictions associated witha keratinization disorder relating to differentiation and proliferation,especially for treating acne vulgaris and comedonal, polymorphous androsacea acnes, nodulocystic acne and acne conglobara, senile acne,secondary acne such as solar, drug or occupational acne and hidradenitissuppurativa;

2) for treating other types of keratinization disorders, especiallyichthyosis, ichthyosiform states, Darrier's disease, palmoplantarkeratoderma, leukoplakia or leucoplakiform states, and cutaneous ormucous (buccal) lichen;

3) for treating other dermatological conditions or afflictionsassociated with a keratinization disorder having an inflammatory and/orimmuno-allergic component and especially all forms of psoriasis whetherthey are cutaneous, mucous or ungula, and even psoriatic rheumatism, orelse cutaneous atopy, such as eczema or respiratory atopy or elsegingival hypertrophy; the compounds may also be used in certaininflammatory conditions that do not exhibit keratinization disorders,such as folliculitis;

4) for treating all dermal or epidermal proliferations, whether benignor malignant, whether or not they are of viral origin, such as verrucas,plane warts, molluscum contagiosum and epidermodysplasia verruciformis,oral or floride papillomatoses and proliferations which may be inducedby ultraviolet light especially in the case of actinic keratoses;

5) for repairing or combating skin aging, whether light-induced orchronological, or for reducing pigmentation, or any pathologiesassociated with chronological and actinic aging;

6) for treating wound-healing disorders or skin ulcers in a preventativeor curative manner, for preventing or repairing striae atrophicae, orelse for promoting wound healing;

7) for combating sebaceous gland disorders such as hyperseborrhea ofacne or simple seborrhea;

8) in treating any skin condition or affliction of fungal origin, suchas tinea pedis and tinea versicolor;

9) in the treatment of dermatological conditions or afflictions havingan immunological component;

10) in the treatment of skin disorders due to exposure to UV radiation;and

11) in the treatment of dermatological conditions or afflictionsassociated with an inflammation or infection of the tissues surroundingthe hair follicle, especially due to a microbial colonization orinfection, especially impetigo, seborrheic dermatitis, folliculitis,sycosis barbae or those involving any other bacterial or fungal agent.

The compositions according to the invention are particularly useful forthe treatment, in a preventative and/or curative manner, of acnevulgaris.

The present invention also features the production of a pharmaceuticalpreparation useful for preventing and/or treating dermatologicalconditions linked to cell differentiation and/or proliferation disordersand/or keratinization disorders, more particularly for the production ofa pharmaceutical preparation useful to prevent and/or treat acnevulgaris.

The compositions according to the invention also find an application inbody and hair hygiene.

The compositions according to the invention particularly find anapplication in the cosmetics field, in particular for treatingacne-prone skin, for hair regrowth, for preventing hair loss, forcombating the greasy appearance of the skin or hair, in protectingagainst the damaging effects of the sun or in treating physiologicallygreasy skin, or for preventing and/or combating light-induced orchronological aging.

In order to further illustrate the present invention and the advantagesthereof, the following specific examples are given, it being understoodthat same are intended only as illustrative and in nowise limitative. Insaid examples to follow, all parts and percentages are given by weight,unless otherwise indicated.

EXAMPLES Example 1 Duos of Gelling Agents

a) Silicate/Gum Tragacanth:

Water qs 100% Adapalene 0.1% Benzoyl peroxide qs 2.5% BPO Propyleneglycol   2% Poloxamer 124 0.2% Disodium EDTA 0.1% Silicate (Veegum K)  2% Gum tragacanth 0.5% Glycerol   2% Sodium docusate 0.05% 

b) Xanthan Gum/Cellulose (Hydroxyethyl Cellulose):

Water qs 100% Adapalene 0.1% Benzoyl peroxide qs 2.5% BPO Propyleneglycol   4% Poloxamer 124 0.2% Disodium EDTA 0.1% Hydroxyethyl cellulose(Natrosol HHX)   2% Xanthan gum (Xantural 18) 0.2% Glycerol   4%

c) Cellulose/Silicate:

Water qs 100% Adapalene 0.1% Benzoyl peroxide qs 2.5% BPO Dipropyleneglycol   4% Poloxamer 124 0.2% Disodium EDTA 0.1% Hydroxyethyl cellulose(Natrosol HHX)   2% Silicate (Veegum HV)   1% Glycerol   4% Sodiumdocusate 0.05% 

Example 2 Trios of Gelling Agents

a) Silicate/Cellulose/Xanthan Gum:

Water qs 100% Adapalene 0.1% Benzoyl peroxide qs 2.5% BPO Propyleneglycol   4% Poloxamer 124 0.2% Disodium EDTA 0.1% Veegum K   2%Hydroxyethyl cellulose (Natrosol HHX) 1.5% Xanthan gum (Xantural 180)0.5% Glycerol microsponges   4% Glycerol   2% Sodium docusate 0.05% 

Specifications at T0:

Macroscopic appearance: White, smooth and shiny productMicroscopic appearance: Good dispersion of both active agents.

Physical Stability:

Stability Time conditions T 1 month T 2 months T 3 months TA Conforms toConforms to Conforms to specifications specifications specifications 40°C. Conforms to Conforms to Conforms to specifications specificationsspecifications Slightly yellowing of Slightly yellowing the product ofthe product

Chemical Stability:

Adapalene:

Assay of the active by internal calibration in HPLC.

At the starting time (T0) the composition is considered to contain 100%of adapalene. Concentration of adapalene measured in % relative to T0:

Stability Time conditions T 0 T 1 month T 2 months T 3 months AT NR NRNR 97.7% 40° C. NR NR NR

Benzoyl Peroxide:

Assay of the active by internal calibration in HPLC.

At the starting time (T0) the composition is considered to contain 100%of benzoyl peroxide. Concentration of benzoyl peroxide measured in %relative to T0:

Stability Time conditions T 0 T 1 month T 2 months T 3 months AT 99.2 NRNR 94.8 40° C. 96.3 81.6% 88.7

b) Silicate/Cellulose/Xanthan Gum:

Water qs 100% Adapalene 0.1% Benzoyl peroxide qs 2.5% BPO Propyleneglycol   5% Poloxamer 124 0.5% Disodium EDTA 0.1% Veegum K   2%Hydroxyethyl cellulose (Methocel E4M) 0.5% Xanthan gum (Xantural 180)0.1% Glycerol   4% Sodium docusate 0.05% 

c) Silicate/Cellulose/Gum Arabic:

Water qs 100% Adapalene 0.1% Benzoyl peroxide qs 2.5% BPO Propyleneglycol   5% Poloxamer 124 0.5% Disodium EDTA 0.1% Veegum K   2%Carboxymethyl cellulose 0.5% Gum arabic 0.1% Glycerol   4% Sodiumdocusate 0.05% 

Each patent, patent application, publication, text and literaturearticle/report cited or indicated herein is hereby expresslyincorporated by reference in its entirety.

While the invention has been described in terms of various specific andpreferred embodiments, the skilled artisan will appreciate that variousmodifications, substitutions, omissions, and changes may be made withoutdeparting from the spirit thereof. Accordingly, it is intended that thescope of the present invention be limited solely by the scope of thefollowing claims, including equivalents thereof.

1. A dermatological/cosmetic composition comprising: at least oneretinoid; benzoyl peroxide; and a gelling system which comprises atleast two categories of compounds, said categories of compounds beingselected from among silicates, cellulose gelling agents andpolysaccharide gums, with the proviso that when at least two gellingagents are selected from among aluminum/magnesium silicate, xanthan gumand hydroxypropyl cellulose, the gelling system is composed of these twogelling agents, or comprises at least one gelling agent different fromthese three compounds.
 2. The dermatological/cosmetic composition asdefined by claim 1, comprising magnesium and aluminum silicates.
 3. Thedermatological/cosmetic composition as defined by claim 1, comprising anamount of silicate ranging from 0.1 to 10% by weight relative to thetotal weight of the composition.
 4. The dermatological/cosmeticcomposition as defined by claim 1, comprising cellulose gelling agentsselected from among methyl cellulose, ethyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose,hydroxymethyl cellulose and hydroxypropyl cellulose.
 5. Thedermatological/cosmetic composition as defined by claim 1, comprising anamount of cellulose gelling agent ranging from 0.1 to 10% by weightrelative to the total weight of the composition.
 6. Thedermatological/cosmetic composition as defined by claim 1, comprising anamount of polysaccharide gum ranging from 0.01 to 5% by weight relativeto the total weight of the composition.
 7. The dermatological/cosmeticcomposition as defined by claim 1, wherein the gelling system comprisesat least one cellulose gelling agent in combination with a silicate. 8.The dermatological/cosmetic composition as defined by claim 1, whereinthe gelling system comprises at least one silicate in combination with apolysaccharide gum.
 9. The dermatological/cosmetic composition asdefined by claim 1, wherein the gelling system comprises at least onepolysaccharide gum in combination with a cellulose gelling agent. 10.The dermatological/cosmetic composition as defined by claim 1, whereinthe gelling system comprises at least one silicate, at least onecellulose gelling agent and at least one polysaccharide gum.
 11. Thedermatological/cosmetic composition as defined by claim 1, comprisingfrom 0.0001 to 20% of retinoid.
 12. The dermatological/cosmeticcomposition as defined by claim 1, wherein the retinoid comprisesadapalene.
 13. The dermatological/cosmetic composition as defined byclaim 1, comprising from 0.0001 to 20% of benzoyl peroxide.
 14. Thedermatological/cosmetic composition as defined by claim 1, wherein thebenzoyl peroxide is encapsulated or free.
 15. Thedermatological/cosmetic composition as defined by claim 1, comprising apropenetrating agent.
 16. The dermatological/cosmetic composition asdefined by claim 15, said propenetrating agent comprising propyleneglycol.
 17. The dermatological/cosmetic composition as defined by claim1, comprising a wetting liquid surfactant.
 18. Thedermatological/cosmetic composition as defined by claim 17, said wettingliquid surfactant comprising a poloxamer.
 19. Thedermatological/cosmetic composition as defined by claim 1, whichcomprises, in water: 2.5% of benzoyl peroxide; 0.1% of adapalene; 0.1%of disodium EDTA; 2%-4% of glycerol; 2%-6% of propylene glycol; 0%-0.05%of sodium docusate; 2%-4% of a gelling system; and 0.2%-0.5% ofPoloxamer
 124. 20. The dermatological/cosmetic composition as defined byclaim 1, which comprises, in water: Adapalene 0.1% Benzoyl peroxide qs2.5% BPO Propylene glycol   4% Poloxamer 124 0.1% Aluminum/magnesiumsilicate   2% Hydroxyethyl cellulose 1.5% Xanthan gum 0.5% Glycerol   2%Sodium docusate 0.05% 


21. A medication comprising the dermatological/cosmetic composition asdefined by claim
 1. 22. A regime or regimen to prevent and/or treat adermatological condition linked to cell differentiation and/orproliferation disorders and/or keratinization disorders, comprisingadministering to an individual in need of such treatment, a thuseffective amount of the dermatological/cosmetic composition as definedby claim
 1. 23. A regime or regimen to prevent and/or treat acnevulgaris, comprising administering to an individual in need of suchtreatment, a thus effective amount of the dermatological/cosmeticcomposition as defined by claim
 1. 24. A regime or regimen for treatingacne-prone skin, for hair regrowth, for preventing hair loss, forcombating the greasy appearance of the skin or hair, for protectingagainst the damaging effects of the sun or for treating physiologicallygreasy skin, or for preventing and/or combating light-induced orchronological aging, comprising administering to an individual in needof such treatment, a thus effective amount of thedermatological/cosmetic composition as defined by claim 1.